How to combine 2 plots (ggplot) into one plot?

Question

By using R, is it possible to place 2 ggplot together (i.e., on the same plot)? I wish to show a trend from 2 different data frames and instead of putting them one next to t

Answer 1

Creating a single combined plot with your current data set up would look something like this

p <- ggplot() +
      # blue plot
      geom_point(data=visual1, aes(x=ISSUE_DATE, y=COUNTED)) + 
      geom_smooth(data=visual1, aes(x=ISSUE_DATE, y=COUNTED), fill="blue",
        colour="darkblue", size=1) +
      # red plot
      geom_point(data=visual2, aes(x=ISSUE_DATE, y=COUNTED)) + 
      geom_smooth(data=visual2, aes(x=ISSUE_DATE, y=COUNTED), fill="red",
        colour="red", size=1)

however if you could combine the data sets before plotting then ggplot will automatically give you a legend, and in general the code looks a bit cleaner

visual1$group <- 1
visual2$group <- 2

visual12 <- rbind(visual1, visual2)

p <- ggplot(visual12, aes(x=ISSUE_DATE, y=COUNTED, group=group, col=group, fill=group)) +
      geom_point() +
      geom_smooth(size=1)

Answer 2

Just combine them. I think this should work but it's untested:

p <- ggplot(visual1, aes(ISSUE_DATE,COUNTED)) + geom_point() + 
     geom_smooth(fill="blue", colour="darkblue", size=1)

p <- p + geom_point(data=visual2, aes(ISSUE_DATE,COUNTED)) + 
     geom_smooth(data=visual2, fill="red", colour="red", size=1)

print(p)

Answer 3

Dummy data (you should supply this for us)

visual1 = data.frame(ISSUE_DATE=runif(100,2006,2008),COUNTED=runif(100,0,50))
visual2 = data.frame(ISSUE_DATE=runif(100,2006,2008),COUNTED=runif(100,0,50))

combine:

visuals = rbind(visual1,visual2)
visuals$vis=c(rep("visual1",100),rep("visual2",100)) # 100 points of each flavour

Now do:

 ggplot(visuals, aes(ISSUE_DATE,COUNTED,group=vis,col=vis)) + 
   geom_point() + geom_smooth()

and adjust colours etc to taste.